Caller ID (Caller Identification) or CNID (calling number identification) is a telephone service that transmits the caller's number to the called party's telephone equipment before the call is answered. Where available, caller ID can also provide a name associated with the calling telephone number. Consumers can today also buy equipment or subscribe to enhanced Caller ID services that show the caller ID on a TV (Television) screen at home when a telephone connected to a PSTN (Public Switched Telephone Network) receives a call provided that a Caller ID service is enabled by a local phone company.
A network architecture called IMS (IP Multimedia Subsystem) has been developed by the 3GPP (3rd Generation Partnership Project) as a platform for handling and controlling multimedia services and sessions, commonly referred to as the IMS network. Thus, an IMS network can be deployed to initiate and control multimedia sessions for IMS-enabled terminals connected to various access networks, regardless of the access technology used. WO-2007/098155-A2 discloses an IMS system interacting with an IPTV system. The disclosed systems enable Caller ID for a caller to an IMS-enabled mobile phone to be displayed on an IPTV. The caller ID is centrally stored in an HSS (Home subscriber Server) as is known in the art and the service is enabled by a specialized service broker function in the IMS network.
Although IMS certainly facilitate new functions and services such as showing Caller ID on a TV screen, it requires new nodes and functionality to be installed in an operator's network and at the moment there are very few persons that have access to IMS-enabled services, e.g. since there currently are few IMS-enabled consumer equipments available on the market for ordinary consumers.